\documentclass{article}
 \title{How to Use Sectioning Comands} \author{} \date{}
\begin{document}
 \maketitle
 \begin{abstract} This is the abstract text. \end{abstract}
 \section{Title of this Section xy}
 \subsection{Title of this Subsection a}
 \subsection{Title of this Subsection b}
 \section{Title of this Section uv}
 \subsection{Title of this Subsection}
 \begin{appendix}
  \section{Commands}
  \section{Tables}
  \section{Data}
 \end{appendix}
\end{document}
